909. Reassessing Pathogens Eligible for the Centers for Disease Control and Prevention’s (CDC’s) National Healthcare Safety Network (NHSN) “Mucosal Barrier Injury-Laboratory Confirmed Bloodstream Infection” Criteria

Background

NHSN Mucosal Barrier Injury-Laboratory Confirmed Bloodstream Infection (MBI-LCBI) includes pathogens likely to cause bloodstream infections (BSI) in some oncology patients. MBI-LCBIs are excluded from central line-associated BSI (CLABSI) reporting to the Centers for Medicare & Medicaid Services. NHSN users have requested other pathogens be added to MBI-LCBI. To make decision, we compared CLABSI pathogen distributions in three NHSN patient location groups.

Methods

We analyzed CLABSI data from hospitals conducting surveillance for ≥ 1 month from January 2014–December 2018 in ≥ 1 MBI high-risk location (leukemia, lymphoma, and adult and pediatric hematopoietic stem cell transplant wards). We compared CLABSI pathogen distributions and rates in MBI high-risk locations to medium-risk (solid tumor, adult and pediatric general hematology-oncology wards) and low-risk locations (adult and pediatric medical, surgical, and medical-surgical wards), and used χ2 tests to compare percentages with statistical significance at P ≤ 0.05.

Results

Overall, 122 hospitals reported 23,578 CLABSIs and 12,961,921 central line (CL)-days (1.81 CLABSIs per 1,000 CL-days) (Table). Percentages of CLABSIs due to three MBI-LCBI pathogens (E. coli, E. faecium, Viridans streptococci) were significantly higher in high- versus low-risk locations, while for other MBI-LCBI pathogens (K. pneumoniae/oxytoca, E. faecalis, Candida spp., Enterobacter spp.) percentages were significantly lower in high-risk locations (Figure). For pathogens not currently in MBI-LCBI, coagulase-negative staphylococci caused similar percentages of CLABSIs across locations, S. aureus caused a significantly higher percentage of CLABSIs in low-risk locations, while PA caused a significantly higher percentage of CLABSIs in high-risk locations.

Table CLABSIs attributed to MBI high-risk, medium-risk, and low-risk locations, NHSN, 2014–2018

Conclusion

Differences in percentages of CLABSIs due to selected pathogens between MBI high-risk and low-risk locations are evident in NHSN data. Lower percentages of Klebsiella and Candida spp. in high-risk locations might be partially due to antimicrobial prophylaxis in oncology patients. Although PA caused a significantly higher percentage of CLABSIs in high-risk locations, the absolute difference was modest. Additional analyses are needed.

Disclosures

All Authors: No reported disclosures

Asymptomatic cerebral embolic signals in symptomatic and asymptomatic carotid artery disease

Transcranial Doppler ultrasound of middle cerebral arteries (MCAs) was used to detect asymptomatic embolic signals in a prospective study in patients with symptomatic and asymptomatic carotid stenosis. Recording from each artery for 20 min, embolic signals were more common ipsilateral to symptomatic arteries (eight of 38) than ipsilateral to asymptomatic arteries (one of 28, P = 0.04), or than in the MCAs of age-matched normal controls (none of 52, P < 0.005). Recording a subgroup of patients revealed that previously embolic-signal negative symptomatic stenoses frequently became embolic-signal positive when recording was repeated on another day. Including all recording periods (mean time: symptomatic 36.2 min, asymptomatic 46.2 min) embolic signals were detected ipsilateral to 13 of 38 symptomatic stenoses but only one of 28 asymptomatic stenoses (P = 0.003). In symptomatic subjects with embolic signals, median number of signals per hour was three (mean 26). One month following carotid endarterectomy embolic signals were not detected except in one patient who continued to experience frequent amaurosis fugax; in this patient following aspirin both symptoms and embolic signals were abolished. These studies suggest asymptomatic embolic signals correlate with clinical risk. Outcome studies are required to determine whether embolic signal detection may allow prediction of stroke risk and monitoring of the effectiveness of therapy. The technique may also prove useful in studying the pathophysiology of cerebral embolism.

The prevalence of lice (Bovicola ovis) infested sheep flocks in Western Australia (1987-1993)

The proportion of wool bale brands with a positive test for sheep lice in baled wool decreased from 29.5% in 1987/88 to 23.2% in 1990/91 before increasing to 38.2% in 1992/93. Changes in the proportion of wool bale brands with a positive test for lice were highly correlated with changes in the Wool Market Price Indicator. The increase in the proportion of positive lice tests since 1990/91 was associated with an increase in failures to eradicate lice from flocks. These failures were partly a consequence of the reduced use of lousicidal treatments, the development of resistance to synthetic pyrethroid chemicals and an increase in the transmission of lice between flocks.